Section 05 Mineral products 25 Salt; sulphur; earths and stone; plastering materials, lime and cement 25 28 Natural borates and concentrates thereof (whether or not calcined), but not including borates separated from natural brine; natural boric acid containing not more than 85 % of H3BO3 calculated on the dry weight. Commodity Code Description 25 28 00 Natural borates and concentrates thereof (whether or not calcined), but not including bo